“We crossed over into more than 2 degrees Fahrenheit warming territory in 2015 and we are unlikely to go back," Gavin Schmidt, the director of NASA’s Goddard Institute for Space Studies, said in a statement. "This shows that what’s happening is persistent, not a fluke due to some weather phenomenon: We know that the long-term trends are being driven by the increasing levels of greenhouse gases in the atmosphere."

NASA's temperature record matches the results of other research agencies, like the National Oceanic and Atmospheric Administration (NOAA), and draws on data collected from over 20,000 weather stations.

Earth's warming trend is accelerating. The last decade was the warmest on record. "Every decade since the 1960s clearly has been warmer than the one before," said Schmidt.